Disclosed herein is a toner prepared by a continuous emulsion aggregation process that exhibits improved gloss and fusing characteristics.
Numerous processes are within the purview of those skilled in the art for the preparation of electrophotographic toners. Emulsion aggregation (EA) is one such method. Emulsion aggregation techniques entail the formation of an emulsion latex of the resin particles by heating the resin using emulsion polymerization as disclosed in, for example, U.S. Pat. No. 5,853,943, the disclosure of which is totally incorporated herein by reference.
Two exemplary emulsion aggregation toners include acrylate based toners, such as those based on styrene acrylate toners as illustrated in, for example, U.S. Pat. No. 6,120,967, and polyester toners, as disclosed in, for example, U.S. Pat. No. 5,916,725, U.S. Pat. No. 7,785,763, and US-2008/0107989, the disclosures of each of which are totally incorporated herein by reference.
Over the last several years there has been an increasing trend in the toner industry towards toner designs that require lower energy to fix. To provide lower fixing energy, manufacturers have been moving towards toner designs that use polyester resins instead of styrene acrylate resins. Polyester technology has enabled designs with lower energy consumption during the fusing process. One drawback of polyester toner designs, however, is the high cost of the polyester latexes. Accordingly, it would be desirable to optimize the viscoelastic properties of styrene acrylate toners to enable lower fusing energy requirements. Doing so, however, would entail changes to the properties of some of the raw materials or replacing some of the raw materials for others. The challenge is to enable the benefit in the fusing performance of the toner while maintaining all other functional properties unchanged.
Accordingly, while known compositions and processes are suitable for their intended purposes, a need remains for toner particles having controlled and tailorable rheology properties. In addition, a need remains for toner particles having controlled and tailorable fusing characteristics. Further, a need remains for toner particles for which the particle shape can be tailored independently of the toner rheology. Additionally, a need remains for toners having the above noted advantages that are prepared by continuous emulsion aggregation methods. There is also a need for toners having the above noted advantages that are prepared by efficient methods in terms of time and energy. Additionally, a need remains for toners having tailorable fusing characteristics without generating a detrimental effect on the blocking characteristics of such toners.